Spring deck for upholstered seating



Feb. 6, 1968 WF. RICHARDSON ET AL I 3,367,648

SPRING DECK FOR UPHOLSTERED SEATING I VFiled Nov. 2s, 1966 fw@ M A fiar/ley a/dson INVENTOR:

United States Patent O SPRING DECK FOR UPHOLSTERED SEATlNG William F. Richardson and Raymond L. McQuitty, Carthage, and Robert 0. saacs, Joplin, Mo., assignors to Flex-O-Lators, Inc., Carthage, Mo., a corporation of Missouri Filed Nov. 23, 1966, Ser. No. 596,514 8 Claims. (Cl. 267--112) ABSTRACT F THE DISCLOSURE This application discloses a spring deck for upholstered seating comprising a planar sheet which is inelastic in its own plane but is resiliently exible transversely to its plane, means aixing the forward edge of said sheet to the rigid frame in such a Way that the rearward portion thereof cannot pivot downwardly, and resiliently extensible members extending between and interconnecting the rearward edge of said sheet to the rearward edge of said frame, said sheet being free of attachment along its side edges, whereby the spring deck formed by said sheet tends to tilt downwardly and rearwardly when loaded.

This invention relates to new and useful improvements in upholstery accessories, and has particular reference to spring decks for upholstered seating structures in furniture, automotive seating and the like. The spring deck in such structures is 4of course the resiliently yieldable sub-structure mounted in the seating frame and over which the padding layers are applied t0 complete the structure.

The principal object of the present invention is the provision of a spring deck which is conducive to better posture on the part of persons using the seating, and which therefore provides greater comfort and less fatigue7 particularly when persons must remain seated for substantial periods of time. Under this generalized statement of the object of the invention, there are two generally more specic objects, namely the provision of a spring deck which tends to urge the users hips rearwardly so that his lower back contacts and is supported by the back structure of the seating structure, and the provision of a spring deck which tends to eliminate or minimize the front-torear hammocking or localized deflection thereof under load. This tendency of most softly-sprung upholstered seating to hammock or wrap around the posterior -of a person sitting on it definitely is a cause of discomfort and fatigue, particularly when sitting for substantial periods of time, and may even cause acute pain to persons having certain types of back ailments.`

Similarly, the habit of many people of shifting their hips forwardly on a seat, so that their spines are curved and their lower backs do not engage and are not supported by the chair back, is a very common cause of seating discomfort and fatigue.

These objects are accomplished in general by the provision of a spring deck comprising a spring fabric sheet secured rigidly along its forward edge to its seat frame, and secured to the frame along its rearward edge by springs which are resiliently extensible in a direction extending from front to rear of the seat. Thus when the deck is loaded, its rearward edge is lowered by the extension of said springs while its forward edge necessarily remains at the same elevation, thereby tending to tilt the deck downwardly t-o the rear, to urge the users hips rearwardly. This tilting effect is increased, and front-torear hammocking of the fabric is minimized, by so constructing the fabric that it has considerable stiffness and resistance to ilexure about an axis extending from side to side of the chair.

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Other objects are simplicity and economy -of construction, efficiency and dependability of operation, and adaptability for use in a wide variety of types and styles of seatlng structures.

With these objects in view, as well as other objects which will appear in the course of the specification, reflerence will be had to the accompanying drawing, where- 1n:

FIG. 1 is a top plan view of a seating frame for upholstered furniture having a spring deck embodying the present invention mounted operatively therein, and

FIG. 2 is an enlarged, foreshortened fragmentary sectional view taken on line II-lI of FIG. 1.

Like reference numerals apply to similar parts throughout both of the views, and the numeral 2 applies generally to the seat frame of an upholstered furniture or automotive chair structure, with the padding and decorative layers omitted. Essentially said frame is rigid, consisting of a front rail 4, rear rail 6 and side rails 8 rigidly joined together to form a rectangular frame which is disposed generally horizontally.

The spring deck forming the central subject matter of the present invention includes a sheet of material which is inelastic in its own plane, but which may be flexed transversely to its plane, and a series of helical tension springs 12. Sheet 10 comprises a `pair of side strands 14 each consisting of a spring wire core 16 (see FIG. 2) enclosed in a sheath 18 of twisted kraft paper or the like, and a series of closely spaced apart cross strands 26 each comprising a spring steel wire extending between side strands 14 in generally parallel relation and secured at their ends to said side strands. As shown, each cross wire is wrapped clampingly about each side strand, with the extreme end thereof being twisted around the portion of the general extent thereof immediately adjacent said side strand, as indicated at 22. This forms a lock preventing the cross wires fr-om pulling loose from the side strands. Also, the sheet may include intermediate strands 24, also formed of twisted kraft paper, extending parallel with and spaced regularly -between side strands 14 each of cross wires 20 piercing each of said intermediate strands at its point of intersection therewith, also as shown in FIG. 2. Said intermediate strands serve to maintain a generally uniform spacing between cross wires 20 throughout their lengths.

One of side strands 14 of sheet 10 is laid along the top edge of front frame rail 4, and secured thereto at intervals along its length by staples 26 bridging said side strand and driven into said rail. The width of the fabric, measured between side strands 14 is less than the frontto-rear depth of frame 2, so that opposite side strand 1'4 of the fabric is then spaced forwardly apart from rear frame rail 6, as shown. The latter rearwardly disposed side strand 14 is then attached to rear frame rail 6 by helical tension springs 12 which are spaced along the full length of said side strand. The forward end of each spring is formed in a hook 30 which is engaged around rearward strand 14, and the rearward end of each spring is formed in a hook 32 which is engaged in a triangular wire hanger 34. Said hanger comprises a length of wire bent in triangular form with the wire ends overlapping at the apex of the triangle. The base side of the hanger is affixed to rear frame rail 6 by a plurality of staples 36 driven into the rail, and the apex of the hanger extends forwardly from said rail. The rear hook 32 of the spring is engaged in the apex of the hanger, engaging the overlapped end portions of the hanger wire so that the spring tension itself tends to prevent accidental opening of the hanger. Thus each spring can pivot vertically about its connection with its associated hanger, without interference either from the hanger or from rail 6. The length of sheet 10, measured in a direction parallel to side strands 14 thereof, is slightly less than the inside distance between side frame rails 8, as clearly shown in FIG. 1, whereby said side rails do not engage or interfere with movement of the spring deck. The usual padding and decorative finishing layers are then applied over the spring deck, usually also extending over and being secured to frame 2. However, these layers are not shown as they are not pertinent to the present invention. Also not shown is the chair back, although it will be understood that said back rises upwardly from rear frame rail 6 in the usual manner. In this connection, it will be understood that sheet 10 of the spring deck spans substantially the entire seating area of the chair, springs 12 of the deck normally being disposed directly beneath the lower edge of the chair back so that no vertical load is normally applied directly thereover.

In operation, it will be seen that when the spring deck has a vertically downward load applied thereto, as by a person sitting on the cushion of which it forms the base, the forward edge thereof of course cannot yield since it is axed directly to the rigid frame, but the rearward edge thereof can and does move downwardly and forwardly, by the yielding of springs 12. This tends to impart to the deck a downward and rearward inclination. This rearward tilting tends to urge the users hips rearwardly on the seat, and to retain them in this rearward position, so that he is obliged to sit in a more upright position without slouching, this better posture being conducive to greater comfort and less fatigue, and also tends to urge his lower back against the chair back, whereby his back is better supported and cushioned. The structure is rendered quiet and free from the grinding, grating and rubbing noises which otherwise would result from relative movement of wires in contact with each other by the paper sheaths 18 of side strands 14. These sheaths also provide good purchase and non-slip engagement between said side strands and cross wires 20. The engagement of hooks 30 and 32 of each spring respectively with rear side strand 14 and its hanger 34 permits free vertical pivoting of the springs so that they never need be transversely flexed by the deck action. Such transverse exing of the helical springs has been found to result in overstraining and breakage thereof, particularly in extended periods of use.

In order to accentuate the tilting action of the deck as described above, it is desirable that the fabric sheet 10 possess a degree of resilient resistance to tlexure about an axis parallel to side strands 14, and the resilience of cross wires 20 supplies this resistance. In fact a complete lack of this resistance, as would occur if fabric 10 were completely pliable, would tend to defeat the effect of the tilting action in urging the users hips rearwardly, since then the fabric would hammock freely between its forward and rearward edges, and the zone directly beneath the users hips would tend to be shifted somewhat forwardly due to the yielding of springs 12. Furthermore, such free hammocking tends to wrap the cushion around the users posterior, and this in itself can be a direct cause of fatigue and discomfort to the user. Therefore, both to reduce the direct discomfort of free and excessive hammocking, and also to improve the tilting action, cross strands 20 are formed of resilient spring steel wire and conjointly provide a considerable degree of resistance to flexure of the sheet about any axis transverse to said wires, so that the sheet tends to remain more nearly planar as its rearward edge is lowered by extension of springs 12. The close spacing of wires 12 also results in the fact that they form a deck which is sufficiently complete to support the padding layers applied thereover and to prevent said padding from working down therebetween.

While stiifening of sheet 10 by means of spring Wires 20 is highly desirable in preventing excessive hammocking and in improving the tilting action, as described, it is also nevertheless true that the use of excessively stiff wires 20 would be objectionable as creating a stiff, boardlike feel to the cushion which would itself be considered uncomfortable and not conforming with modern requirements for a feeling of softness Therefore, some degree of flexure of the sheet, resulting in a degree of hammocking thereof, is desirable so long as it is not excessive. In the present structure, the total vertical yielding of the loaded zone of the deck fabric is accomplished partially by tilting of the fabric as allowed by extension of springs 12, and partially by flexure of the fabric itself as a result of the flexure of wires 20, and the proportion of the total yield accomplished by the two actions may be varied and adjusted by regulating the relative strengths of springs 12 and wires 20, to produce a deck having the desired characteristics. As a practical matter, since it is almost impossible to prevent a substantial degree of flexure of wires 20 when the deck is loaded, due to the considerable length or span of said wires, it is generally desirable to install springs 12 under a very slight tension, so that they can be extended to allow rearward tilting of the fabric, without causing excessive additional ilexure of wires 20.

The stiffness of the spring wire cores 16 of side strands 14 which are preferably heavier and stiffer than wires 20 provides structural strength to fabric 10 so that it will hold its form permanently, and permits the use of a smaller number of stronger springs 12, as compared to the larger number of weaker springs which would be required if said side strands were more flexible, 'and also a smaller number of staples 26 at the forward edge of the deck. This is important since labor time and costs represent a large proportion of the price of seating structures. The presently described deck structure is extremely simple and economical and can be installed easily with a minimum of labor time. Also, the spacing of springs 12 is optional, and could be varied if desired. For instance, in some cases it may be preferable to space said springs more closely in a zone midway between side rails 8, this ordinarily being the zone of maximum loading and wear.

While we have shown and described a specific embodiment of our invention, it will be readily apparent that many minor changes of structure and operation could be made without departing from the spirit of the invention as defined by the scope of the appended claims.

What we claim as new and desire to protect by Letters Patent is:

1. In combination:

(a) a rigid seating frame having front, rear and side rails and disposed generally horizontally,

(b) a generally rectangular sheet of material inelastic in its own plane but capable of exure transversely to its plane,

(c) means securing the forward edge of said sheet nonpivotally to said front rail, whereby the rearward portion of said sheet can move downwardly only by flexure of said sheet, the rearward edge of said sheet being spaced forwardly from said rear rail,

(d) a series of resiliently extensible elongated members each secured at one end to the rearward edge of said sheet at intervals therealong, and

(e) means securing the opposite end of each of said resiliently extensible members to said rear rail, whereby said members and said sheet are maintained taut, said sheet being free of attachments along its side edges, whereby when said sheet is top-loaded, it tends to tilt downwardly and rearwardly by reason of the yielding of said resiliently extensible elongated members.

2V. The combination as recited in claim 1 wherein said sheet is formed of a material having a degree of resilient resistance to flexure about any axis generally parallel t0 the front and rear edges thereof.

3. The combination as recited in claim 1 wherein said sheet includes as elements thereof a series of spaced apart spring wires which are generally parallel and which extend transversely to the forward and rearward edges thereof.

4. The combination as recited in claim 1 wherein said sheet comprises:

(a) a pair of side strands respectively dening the forward and rearward edges thereof, and

(b) a series of relatively closely spaced apart, generally parallel spring wire cross strands extending between and each axed at its opposite ends to said side strands.

5. The combination as recited in claim 4 wherein each of said side strands includes a spring steel wire relatively heavier and stiffer than said cross Wires, and wherein said means securing the forward edge of said sheet to said front rail, and said resiliently extensible members, have engagement only with said side strands.

6. The combination as recited in claim 5 wherein the spring steel Wire of each of said side strands is provided with an enclosing sheath of a soft, indentable material, and wherein said cross wires, front securing means and resiliently extensible members have engagement only with the sheaths of said side strands.

7. The combination as recited in claim 1 wherein each of said resiliently extensible members constitutes an elongated helical spring secured at its forward end to the rearward edge of said sheet, and is provided at its rear- Ward end with a hook, and wherein said means securing the opposite end of said spring to said rear rail comprises a vertically opening loop member 'aixed to said rear rail and extending forwardly thereof, the hook of said spring being engaged in said loop member whereby to permit vertical pivotal movement of said spring.

8. A spring deck for use in a rigid seating frame having front, rear and side rails, said spring deck comprising:

(a) a sheet of planar material inelastic in its vown plane :but s-ubject to resilient exure transversely to its plane, said sheet being adapted to extend over substantially the entire seating area of said frame, and comprising a pair of strands respectively defining the front and rear edges thereof, each of said strands having a relatively stiff spring Wire core and having an enclosing sheath of a soft, indentable material, and a series of relatively closely spaced, relatively less stiff, generally parallel spring wires extending transversely between s'aid strands at intervals along the entire lengths of the latter, each of said wires being secured to each of said strands by twisting it about said strand in clamping engagement With the sheath thereof and then about itself,

(b) means adapted to secure the forward edge of said sheet to said front frame rail, the width of said sheet in a direction from front to rear of said frame being less than the distance between Said front and rear rails, and

(c) elongated resiliently extensible members each secured at one end to the rearward edge of said sheet and adapted to be secured at its opposite end to said rear rail.

References Cited UNITED STATES PATENTS 1,876,305 9/1932 Kroehler 267-112 2,010,578 8/1935 Bank 267-112 2,158,441 5/1939 Thun 267-112 2,788,845 4/1957 Bond et al. 267-112 3,195,955 7/1965 Richardson et al. 267-112 X ARTHUR L. LA POINT, Primary Examiner. 

